Once daily formulations of tetracyclines

ABSTRACT

Disclosed are once-daily formulations containing tetracyclines, especially doxycycline. Such formulations are useful, for instance, for the treatment of collagenase destructive enzyme-dependent diseases, such as periodontal disease and acne, and acute and chronic inflammatory disease states, such as rosacea and arthritis.

FIELD OF THE INVENTION

The present invention is concerned with once-daily compositions oftetracyclines, which can be used for the treatment of acute or chronicdiseases, for instance those with inflammatory components. Morespecifically, the present invention is directed to a pharmaceuticalcomposition of doxycycline for the treatment of diseases or conditionsin which collagen destructive enzymes or molecules involved with suchthings as inflammation are contributing factors, and which is a oncedaily formulation. The compositions are especially useful for treatingsuch common disease states as periodontal disease, rosacea, dry eye,acne and rheumatoid arthritis.

BACKGROUND OF THE INVENTION

Conventionally, doxycycline and related tetracyclines are used as broadspectrum antibiotics to treat various bacterial infections.Tetracyclines interfere with the protein synthesis of Gram positive andGram-negative bacteria by preventing the binding of aminoacyl-tRNA tothe ribosome. Their action is bacteriostatic (preventing growth ofbacteria) rather than killing (bactericidal). The doses commonly usedfor doxycycline to achieve the antibiotic effect are 100 mg and 50 mg.

Doxycycline, as well as other tetracyclines, also has other therapeuticuses in addition to its antibiotic properties. For example, doxycyclineis known to inhibit the activity of collagen destruction enzymes such ascollagenase, gelatinase, and elastase. Its collagenase inhibitionactivity has been used to treat periodontal disease. For anotherexample, doxycycline can inhibit lipase produced by the bacterium P.acnes and thus reduces the availability of free fatty acids that areinvolved in inflammation. Doxycycline may also reduce inflammation byreducing cytokine levels so that the integrity of the follicular wall ispreserved. Thus, doxycycline also has the potential in treating skindiseases, such as acne.

Investigators have found that sub-antimicrobial doses of tetracyclinesare useful in the treatment of various ailments, although the mechanismsresponsible for the effects are not entirely clear. For instance, U.S.Pat. No. 6,455,583 discloses treating meibomian gland disease by oraladministration of non-antimicrobial amounts of a tetracycline to thepatient. U.S. Pat. No. 6,100,248 teaches a method of inhibiting cancergrowth by administering tetracyclines which have been chemicallymodified to attenuate or delete their antibacterial activity. Methods toreduce collagenolytic enzymes by administration of amounts of atetracycline that are generally lower than the normal amounts used forantimicrobial therapy are disclosed in U.S. Pat. No. 4,666,897. Thepatents cited in this paragraph are hereby incorporated herein byreference.

In the market, there are two implantable products for site-specific usein the treatment of periodontal disease. The PerioChip® is a small,orange-brown chip, which is inserted into periodontal pockets. EachPerioChip® contains 2.5 mg of chlorhexidine gluconate in abiodegradable, resorbable matrix. It is recommended that PerioChip®treatment be administered once every three months in pockets that remainat 5 mm or deeper. A second product, Atridox®, is an injectable,resorbable gel, which provides the subgingival controlled-release of42.5 mg doxycycline for approximately one week. Additionally, there isnow available a new oral medication called Periostat®, which delivers 20mg doxycycline systemically as a collagenase inhibitor used in patientswith adult periodontal disease. Most people would prefer to take a pillto the implant. However, Periostat® requires twice daily dosing andraises concerns about patient compliance. Thus, it would be highlybeneficial to develop a once-a-day formulation for doxycycline.

While doxycycline is generally effective for treating infection, the useof doxycycline can lead to undesirable side effects. For example, thelong-term administration of the antibiotic doxycycline can reduce oreliminate healthy biotic flora, such as intestinal flora, and can leadto the production of antibiotic resistance organisms or the overgrowthof yeast and fungi. Because of the undesirable side effects from itsantibiotic properties, there is a need for a unique dose and an improvedformulation to deliver doxycycline such that the anti-collagendestructive enzymes or other such beneficial effect of tetracyclines,especially doxycycline, is attained, but antibacterial effects areavoided.

SUMMARY OF THE INVENTION

The present invention is in its broadest sense directed topharmaceutical compositions of tetracyclines designed to provide anextended release profile in vivo of levels of active ingredient that atsteady state are high enough to be effective to have a beneficial effectin the treatment of a disease or condition, but not as high as to exertan antibacterial effect. Such pharmaceutical compositions are formulatedinto dosage forms that can be taken once a day. One object of thepresent invention is to provide a pharmaceutical composition ofdoxycycline, which can be given once a day yet meet the steady stateblood levels required for the treatment or prevention of diseases orconditions caused by overproduction of collagenase, such as periodontaldisease, or other biochemicals associated with certain disease stateswhich could be regulated with doxycycline, such as conditions involvinginflammation, without the undesirable effects of long term antibioticactivity.

One object of the present invention is to provide a once-dailypharmaceutical composition containing doxycycline that will give steadystate blood levels of doxycycline of a minimum of about 0.1 μg/ml and amaximum of about 1.0 μg/ml.

In one aspect of the invention is an immediate release formulation ofdoxycycline containing less than 50 mg but more than 25 mg, preferablyabout 40 mg. doxycycline base.

In another aspect, the invention is directed to a pharmaceuticalcomposition of doxycycline that contains an immediate release (IR)component of the drug and a delayed release (DR) component of the drug,which are combined into one dosage unit for once-daily dosing. Thecomponents can be present in various ratios, although preferred areratios of about 70:30 to about 80:20, and most preferred 75:25, IR:DR,with the total dosage of doxycycline being less than about 50 mg. andpreferably about 40 mg. The ratio refers to the dose breakdown betweenIR and DR, e.g., 80:20 means 80% of 40 mg is from IR portion and 20% of40 mg is from DR portion.

Yet another object of the invention is to provide a method for treatingdiseases or conditions in which collagenase is produced in excessiveamounts causing pathological destruction of tissues, such as periodontaldisease, rheumatoid arthritis, hyperparathyroidism, diabetes and acne,by administering the once-daily dosage of doxycycline. See, e.g., U.S.Pat. No. 4,666,897 of Golub.

Another object of the present invention is to provide a method forsystemic treatment of rosacea, a dermatological condition of humans, byadministering the once-daily dosage of doxycycline according to thepresent invention.

Another object of the invention is to provide processes for preparingthe once-daily compositions of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows dissolution profiles for doxycycline monohydrateimmediate-release beads within the scope of the present invention, whichwere determined by utilizing a computer algorithm that is based on acompartmental absorption and transit model to deconvolute in vivorelease profiles from in vivo human plasma data. The in silico model wasfirst validated and tested using human plasma data from immediaterelease dosage forms.

FIG. 2 shows in silico dissolution profiles for doxycycline monohydratedelayed-release beads.

FIG. 3 shows in silico dissolution profiles for the composite capsuleswith 75% of immediate-release beads and 25% of delayed-release beads.

FIG. 4 shows predicted blood levels vs. time profiles at steady statefor various treatments (i.e., 40 mg once-a-day IR formula, 40 mgonce-a-day IR and DR combinations at 70:30 and 80:20 ratios, andtwice-a-day 20 mg doxycycline treatment).

FIG. 5 represents the pharmacokinetic profiles of 75:25 IR:DR (40 mg.)formulation at day 1 and day 7 (steady state) in humans.

FIG. 6 compares the pharmacokinetic curves of 75:25 IR:DR (40 mg.)formulation with the Periostat® 20 mg. twice daily dosage form.

DETAILED DESCRIPTION OF THE INVENTION

While the following description is directed primarily to doxycycline, itis contemplated that the present invention is applicable to othertetracyclines, particularly other tetracyclines that have similar invivo absorption profiles as doxycycline, more specifically tetracyclinesthat have a similar region of absorption in the gastrointestinal tractas doxycycline. Different kinds of tetracyclines and the beneficialeffects on various disease states are disclosed in, for example, WO02/083106 and U.S. Pat. No. 6,638,922, each of which are incorporated intheir entireties herein by reference.

The present invention can be accomplished by providing an orallyadministered composition of, as an example, doxycycline which isdesigned to provide certain steady state blood levels of the drug, whilein a formulation that requires that the mammal, preferably human, totake only one dosage a day. The compositions of the present inventionare intended to be useful in lieu of multiple daily dosing, such astwice-daily dosing, of compositions that achieve the same effects. Thepreferred blood level of doxycycline, or other tetracyclines ofcomparable physiological and absorption properties, is between about 0.1and about 1.0 μg/ml at the steady state. Preferably, the blood levelsstay within the preferred blood level, with daily dosing, for the entirecourse of treatment. More preferably, the blood levels are between about0.3 μg/ml and about 0.8 μg/ml.

The above blood serum levels allow for the desired anti-collagenase andanti-inflammatory activity of doxycycline, without being accompanied byundesirable antibiotic activity. It was surprisingly found that theselevels can be accomplished with a single daily dose of an immediaterelease formulation containing below 50 mg. but more than 25 mg.,preferably about 40 mg. doxycycline base.

“About” means within the pharmaceutically acceptable limits found in theUnited States Pharmacopia (USP-NF 21), 2003 Annual Edition, or availableat www.usp.org, for amount of active pharmaceutical ingredients. Withrespect to blood levels, “about” means within FDA acceptable guidelines.

By “immediate release” formulation is meant a dosage form that isintended to release substantially all of the active ingredient onadministration with no enhanced, delayed or extended release effect.Such a composition of doxycycline can be in the form of a liquidsuspension or solution, or as a solid such as a tablet, pellet (usedinterchangeably with bead or beadlet herein), particle, capsule or gel.Preferred in the present invention are tablets, or beadlets in acapsule.

As pharmaceutically active ingredients, any form of the tetracyclinecompound can be used provided it will comply with the required bloodserum levels of the present invention. Doxycycline, for instance, iscommonly used in pharmaceutical formulations under two chemical forms:the monohydrate form and the hyclate form. The monohydrate is the basemolecule hydrated with one molecule of water and is used in theformulation of capsules and, in some markets, powder oral suspensions(to be reconstituted with water). The hyclate is a hydrochloric acidsalt solvated with water and ethanol and is typically used in theformulation of capsules or tablets. The amount of doxycycline in thecompositions of the present invention refers to doxycycline base. Also,in the compositions of the present invention there may be more than oneactive ingredient. That is, the doxycycline can be combined with anothertherapeutic or nutritional substance in the dosage forms.

Immediate Release Dosage Forms

There are many ways known in the art to formulate such immediate releasedosage forms. For instance, an immediate release tablet can be preparedby mixing doxycycline with a bulking agent such as microcrystallinecellulose, for example, AVICEL® (FMC Corp.) or EMCOCEL® (Mendell Inc.);dicalcium phosphate, for example, EMCOMPRESS® (Mendell Inc.); calciumsulfate, for example, COMPACTROL® (Mendell Inc.); and starches, forexample, STARCH 1500. Additionally, one can add a disintegrating agent,such as microcrystalline cellulose, starches, crospovidone, for example,POLYPLASDONE XL® (International Specialty Products); sodium starchglycolate, for example, EXPLOTAB® (Mendell Inc.); and croscarmellosesodium, for example, AC-DI-SOL® (FMC Corp.). Antiadherants and glidantsemployed herein can include talc, cornstarch, silicon dioxide, sodiumlauryl sulfate, colloidal silica dioxide, and metallic stearates.

Lubricants may be employed, such as magnesium stearate, calciumstearate, sodium stearate, stearic acid, sodium stearyl fumarate,sterotex, talc, waxes and the like. Binding agents may be employed, suchas polyvinyl pyrollidone, starch, methylcellulose, hydroxypropylmethylcellulose, carboxymethyl cellulose, and the like.

The present invention is preferably formulated into a tablet preparedusing methods known in the art, including a wet granulation method and adirect compression method. The oral tablets are prepared using anysuitable process known to the art. See, for example, Remington'sPharmaceutical Sciences, 18^(th) Edition, A. Gennaro, Ed., Mack Pub. Co.(Easton, Pa. 1990), Chapters 88-91, the entirety of which is herebyincorporated by reference. Typically, the active ingredient,doxycycline, is mixed with pharmaceutically acceptable excipients (e.g.,the binders, lubricants, etc. listed above) and compressed into tablets.Preferably, the dosage form is prepared by a wet granulation techniqueor a direct compression method to form uniform granulates.Alternatively, the active ingredient(s) can be mixed with the granulateafter the granulate is prepared. The moist granulated mass is then driedand sized using a suitable screening device to provide a powder, whichcan then be filled into capsules or compressed into matrix tablets orcaplets, as desired.

In a preferred embodiment, the tablets are prepared using the directcompression method. The direct compression method offers a number ofpotential advantages over a wet granulation method, particularly withrespect to the relative ease of manufacture. In the direct compressionmethod, at least one pharmaceutically active agent and the excipients orother ingredients are sieved through a stainless steel screen, such as a40 mesh steel screen. The sieved materials are then charged to asuitable blender and blended for 10 minutes with an intensifier bar forthree minutes. The blend is then compressed into tablets on a rotarypress using appropriate tooling.

As mentioned above, another preferred dosage form for the immediaterelease composition is a capsule containing immediate release beadletsor pellets. Methods for making such pellets are set forth in the sectionbelow (i.e., the IR pellets). The pellets are filled into capsules, forinstance gelatin capsules, by conventional techniques.

Combination IR/DR Dosage Forms

In another embodiment of the present invention is a composition having asubstantially immediate release dose of doxycycline, followed by atleast one additional dose at a predetermined time, in a unit dosage. Thefirst immediate release dose of the composition can be in the form ofpowder, granule, beadlet, or tablet; the second delayed-release portioncan be coated granular, coated beadlet, coated tablet, or uncoatedmatrix tablet. The ratio between the immediate-release portion, orcomponent, and the delayed-release portion, or component, can be used toadjust the in vitro drug release profile and in vivo blood concentrationprofile. By providing such a drug release profile, the compositionseliminate the need for a second dose for the day. Additionally, thetotal dose of doxycycline is below 50 mg. to avoid the undesirable sideeffects from its antibiotic properties, but more than 25 mg. to achievethe anti-collagenase and/or anti-inflammatory effect.

Several dosage form variations can be used to achieve a product withthese attributes. For example, an immediate-release powder blend can beencapsulated with a delayed-release tablet or delayed-release pellets. Afurther example is an immediate-release tablet and a delayed-releasetablet that are prepared separately and encapsulated into an appropriatesized capsule shell. Or, for example, a delayed-release tablet can beused as a core and the immediate-release portion can be compressed as anouter layer using a press coater or overcoated using a drug layeringtechnique, both techniques of which can be found in Gunsel and Dusel,Chapter 5, “Compression-coated and layer tablets”, in PharmaceuticalDosage Forms:Tablets, Second Edition, Volume 1, Edited by H. A.Lieberman, L. Lachman, and J. B. Schwartz, Marcel Dekker, Inc. New Yorkand Basel (1990).

Multiparticulate Capsules

As a preferred embodiment, the IR/DR composition of doxycycline is inthe form of a capsule containing beadlets. At present, it is preferredto have two different types of units in a single form multiple-unitdosage form.

The first unit is an immediate release dosage form, preferably in pelletform. This component can also be a powder if desired or necessary. Ineither case, the dosage form may have a surface-active agent such assodium lauryl sulfate, sodium monoglycerate, sorbitan monooleate,polyoxyethylene sorbitan monooleate, glyceryl monostearate, glycerylmonooleate, glyceryl monobutyrate, any one of the Pluronic line ofsurface-active polymers, or any other suitable material with surfaceactive properties or any combination of the above. Preferably, thesurface-active agent would be a combination of sodium monoglycerate andsodium lauryl sulfate. The concentration of these materials in thiscomponent can range from about 0.05 to about 10.0% (W//W).

Other excipient materials that can be employed in making drug-containingpellets are any of those commonly used in pharmaceutics and should beselected on the basis of compatibility with the active drug and thephysicochemical properties of the pellets. These include, for instance:binders such as cellulose derivatives such as methylcellulose,hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethylcellulose, polyvinylpyrrolidone, polyvinylpyrrolidone/vinylacetate copolymer and the like; disintegration agents such ascornstarch, pregelatinized starch, cross-linked carboxymethylcellulose(AC-DI-SOL®), sodium starch glycolate (EXPLOTAB®), cross-linkedpolyvinylpyrrolidone (PLASDONE® XL), and any disintegration agents usedin tablet preparations, which are generally employed in immediaterelease dosages such as the one of the present invention; filling agentssuch as lactose, calcium carbonate, calcium phosphate, calcium sulfate,microcrystalline cellulose, dextran, starches, sucrose, xylitol,lactitol, mannitol, sorbitol, sodium chloride, polyethylene glycol, andthe like; surfactants such as sodium lauryl sulfate, sorbitanmonooleate, polyoxyethylene sorbitan monooleate, bile salts, glycerylmonostearate, the PLURONIC® line (BASF), and the like; solubilizers suchas citric acid, succinic acid, fumaric acid, malic acid, tartaric acid,maleic acid, glutaric acid sodium bicarbonate and sodium carbonate andthe like; and stabilizers such as any antioxidation agents, buffers,acids, and the like, can also be utilized.

The pellet can be made by, for example, simple granulation, followed bysieving; extrusion and marumerization; rotogranulation; or anyagglomeration process that results in a pellet of reasonable size androbustness. For extrusion and marumerization, the drug and otheradditives are granulated by addition of a binder solution. The wet massis passed through an extruder equipped with a certain size screen, andthe extrudates are spheronized in a marumerizer. The resulting pelletsare dried and sieved for further applications. One may also usehigh-shear granulation, wherein the drug and other additives aredry-mixed and then the mixture is wetted by addition of a bindersolution in a high shear-granulator/mixer. The granules are kneadedafter wetting by the combined actions of mixing and milling. Theresulting granules or pellets are dried and sieved for furtherapplications.

As stated earlier, it is also possible to have this immediate releasecomponent as a powder, although the preferred form is a pellet due tomixing and de-mixing considerations.

Alternatively, the immediate release beadlets or pellets of thecomposition can be prepared by solution or suspension layering, wherebya drug solution or dispersion, with or without a binder, is sprayed ontoa core or starting seed (either prepared or a commercially availableproduct) in a fluid bed processor or other suitable equipment. The coresor starting seeds can be, for example, sugar spheres or spheres madefrom microcrystalline cellulose. The drug thus is coated on the surfaceof the starting seeds. The drug-loaded pellets are dried for furtherapplications.

The second unit should have a delayed release (DR) profile, and needs tobe able to address the changing pH of the GI tract, and its effect onthe absorption of doxycycline or other tetracycline. This pellet shouldhave all of the ingredients as mentioned for the first unit pellet, aswell as optionally some organic acid that will be useful to reduce thepH of the microenvironment of the pellet, and thus facilitatedissolution. These materials are, but not limited to, citric acid,lactic acid, tartaric acid, or other suitable organic acids. Thesematerials should be present in concentrations of from about 0 to about15.0% (w/w); preferably these materials would be present inconcentrations of from about 5.0 to about 10.0 percent (w/w). Theprocess for manufacturing these pellets is consistent with the processdescribed above for the first unit pellet.

Unlike the first unit pellet, the second unit delayed-release componenthas a controlling coat applied to the surface of the pellet such thatthe release of the drug from the pellet is delayed. This is accomplishedby applying a coating of enteric materials. “Enteric materials” arepolymers that are substantially insoluble in the acidic environment ofthe stomach, but are predominantly soluble in intestinal fluids atspecific pHs. The enteric materials are non-toxic, pharmaceuticallyacceptable polymers, and include, for example, cellulose acetatephthalate (CAP), hydroxypropyl methylcellulose phthalate (HPMCP),polyvinyl acetate phthalate (PVAP), hydroxypropyl methylcelluloseacetate succinate (HPMCAS), cellulose acetate trimellitate,hydroxypropyl methylcellulose succinate, cellulose acetate succinate,cellulose acetate hexahydrophthalate, cellulose propionate phthalate,copolymer of methylmethacrylic acid and methyl methacrylate, copolymerof methyl acrylate, methylmethacrylate and methacrylic acid, copolymerof methylvinyl ether and maleic anhydride (Gantrez ES series), ethylmethyacrylate-methylmethacrylate-chlorotrimethylammonium ethyl acrylatecopolymer, natural resins such as zein, shellac and copal collophorium,and several commercially available enteric dispersion systems (e.g.,EUDRAGIT® L30D55, EUDRAGIT® FS30D, EUDRAGIT® L100, KOLLICOAT® EMM30D,ESTACRYL® 30D, COATERIC®, and AQUATERIC®). The foregoing is a list ofpossible materials, but one of skill in the art would recognize that itis not comprehensive and that there are other enteric materials thatwould meet the objectives of the present invention of providing for adelayed release profile. These coating materials can be employed incoating the surfaces in a range of from about 1.0% (w/w) to about 50%(w/w) of the pellet composition. Preferably these coating materialsshould be in a range of from about 20 to about 40 percent (w/w). Thepellets may be coated in a fluidized bed apparatus or pan coating, forexample.

With the enteric coated pellets, there is no substantial release ofdoxycycline in the acidic stomach environment of approximately below pH4.5. The doxycycline becomes available when the pH-sensitive layerdissolves at the greater pH of the small intestine; after a certaindelayed time; or after the unit passes through the stomach. Thepreferred delay time is in the range of two to six hours.

As a variation of this embodiment, the DR pellet contains layers of thedoxycycline, separated by protective layers, and finally an entericcoating, resulting in a “repeat-action” dosage delivery. Such a dosageform may meet the blood level requirements of the release profile of thepresent invention if the release of the doxycycline, or othertetracycline, in all of the layers is within the absorption window forthe drug.

An overcoating layer can further optionally be applied to the IR/DRpellets of the present invention. OPADRY®, OPADRY II® (Colorcon) andcorresponding color and colorless grades from Colorcon can be used toprotect the pellets from being tacky and provide colors to the product.The suggested levels of protective or color coating are from 1 to 6%,preferably 2-3% (w/w).

Many ingredients can be incorporated into the overcoating formula, forexample to improve the coating process and product attributes, such asplasticizers: acetyltriethyl citrate, triethyl citrate, acetyltributylcitrate, dibutylsebacate, triacetin, polyethylene glycols, propyleneglycol and others; lubricants: talc, colloidal silica dioxide, magnesiumstearate, calcium stearate, titanium dioxide, magnesium silicate, andthe like.

The delayed release and immediate release units are combined in thedosage form (in this instance, the different pellets are put intocapsules) in a predetermined ratio, preferably about 70:30 to about80:20, most preferably 75:25 (IR/DR), which will achieve the desiredsteady state blood serum levels with only once-daily dosing.

The composition, preferably in beadlet form, can be incorporated intohard gelatin capsules, either with additional excipients, or alone.Typical excipients to be added to a capsule formulation include, but arenot limited to: fillers such as microcrystalline cellulose, soypolysaccharides, calcium phosphate dihydrate, calcium sulfate, lactose,sucrose, sorbitol, or any other inert filler. In addition, there can beflow aids such as fumed silicon dioxide, silica gel, magnesium stearate,calcium stearate or any other material imparting flow to powders. Alubricant can further be added if necessary by using polyethyleneglycol, leucine, glyceryl behenate, magnesium stearate or calciumstearate.

The composition may also be incorporated into a tablet, in particular byincorporation into a tablet matrix, which rapidly disperses theparticles after ingestion. In order to incorporate these particles intosuch a tablet, a filler/binder must be added to a table that can acceptthe particles, but will not allow their destruction during the tabletingprocess. Materials that are suitable for this purpose include, but arenot limited to, microcrystalline cellulose (AVICEL®), soy polysaccharide(EMCOSOY®), pre-gelatinized starches (STARCH® 1500, NATIONAL® 1551), andpolyethylene glycols (CARBOWAX®). The materials should be present in therange of 5-75% (w/w), with a preferred range of 25-50% (w/w).

In addition, disintegrants are added in order to disperse the beads oncethe tablet is ingested. Suitable disintegrants include, but are notlimited to: cross-linked sodium carboxymethyl cellulose (AC-DI-SOL®),sodium starch glycolate (EXPLOTAB®, PRIMOJEL®), and cross-linkedpolyvinylpolypyrrolidone (Plasone-XL). These materials should be presentin the rate of 3-15% (w/w), with a preferred range of 5-10% (w/w).

Lubricants are also added to assure proper tableting, and these caninclude, but are not limited to: magnesium stearate, calcium stearate,stearic acid, polyethylene glycol, leucine, glyceryl behenate, andhydrogenated vegetable oil. These lubricants should be present inamounts from 0.1-10% (w/w), with a preferred range of 0.3-3.0% (w/w).

Tablets are formed, for example, as follows. The particles areintroduced into a blender along with AVICEL®, disintegrants andlubricant, mixed for a set number of minutes to provide a homogeneousblend which is then put in the hopper of a tablet press with whichtablets are compressed. The compression force used is adequate to form atablet; however, not sufficient to fracture the beads or coatings.

It will be appreciated that the multiple dosage forms of the presentinvention can deliver dosages of pharmaceutically active doxycycline, orother tetracycline, to achieve the desired levels of the drug in arecipient over the course of about 24 hours at steady state with asingle daily oral administration.

The present invention also provides a method for treating a mammal withdoxycycline, or other tetracycline. The method involves administering adoxycycline, or other tetracycline, composition according to the presentinvention to a mammal, preferably a human, in need of theanti-collagenase or anti-inflammatory activity of doxycycline or othertetracycline substantially without accompanying antibiotic activity.Systemic administration is preferred, and oral administration is mostpreferred.

Using the compositions of the present invention, the steady state bloodlevels of doxycycline or other tetracycline of a minimum of about 0.1μg/ml, preferably about 0.3 μg/ml and a maximum of about 1.0 μg/ml, morepreferably about 0.8 μg/ml, can be achieved to treat diseases withincreased collagenase production, such as periodontal, skin diseases andthe like, as well as inflammatory states. Indeed, any disease statetreatable with sub-antimicrobial blood levels of a tetracycline given inmultiple daily dosages can also be treated using the correspondingonce-daily formulations of the present invention.

The invention will now be illustrated by the following examples, whichare not to be taken as limiting.

EXAMPLES Example 1 Preparation of Layered IR Pellets ContainingDoxycycline Monohydrate

A dispersion of doxycycline monohydrate was prepared as follows: To5.725 kilograms of deionized water were added 0.113 kilogramhydroxypropyl methylcellulose and 1.5 kilograms of doxycyclinemonohydrate, followed by moderate mixing, using a stirring paddle for 30minutes. The drug dispersion was sprayed onto sugar seeds (30/35 mesh)in a 9″ Wurster Column of a GPCG-15 fluid bed processor. Until theentire dispersion was applied, the pellets were dried in the column for5 minutes. The drug-loaded pellets were discharged from the WursterColumn and passed through a 20 mesh screen. A protective coat (e.g.,OPADRY® beige) also can be applied onto the IR beads to provide color orphysical protection. FIG. 1 shows a typical dissolution profile fordoxycycline monohydrate immediate-release beads.

Example 2 Preparation of Enteric Coated Pellets Containing DoxycyclineMonohydrate

The EUDRAGIT® L30D55 coating dispersion was prepared by adding 0.127kilogram of triethyl citrate into 3.538 kilograms of EUDRAGIT® L30D55(solid content: 1.061 kilograms) and stirring for at least 30 minutes.Talc 0.315 kilogram was dispersed into 2.939 kilograms of deionizedwater. The plasticized EUDRAGIT® L30D55 was combined with the talcdispersion and screened through a 60 mesh screen. The resulting combineddispersion was sprayed onto drug-loaded pellets (3.5 kilograms) preparedaccording to Example 1 in a 9″ Wurster Column of a GPCG-15 fluid bedprocessor. A protective coat (e.g., OPADRY® beige) may be applied ontothe DR beads to provide color or physical protection. FIG. 2 shows atypical dissolution profile for doxycycline monohydrate delayed-releasebeads.

Example 3 Encapsulation of Drug-Loaded Pellets and Enteric CoatedPellets

Capsules can be prepared by filling the drug-loaded pellets and entericcoated pellets individually into appropriate sized capsule shells. Theratio between the drug-loaded pellets and enteric-coated pellets can be100:0 to 70:30. For example, at the ratio of 75:25, the fill weight ofdrug-loaded pellets can be calculated based on the actual potency of thedrug-loaded pellets to deliver 30 mg doxycycline; the fill weight ofenteric-coated pellets also can be calculated based on the actualpotency of the enteric-coated pellets to deliver 10 mg doxycycline.Romoco CD5 or MG-2 pellet filling machine can be used to accurately fillthe pellets into the desired capsule shells. FIG. 3 shows the typicaldissolution profile for the composite capsules with 75% ofimmediate-release beads and 25% of delayed-release beads.

Example 4 Preparation of Delayed Tablet Containing DoxycyclineMonohydrate

Doxycycline monohydrate 0.5625 kilogram was blended with 3.15 kilogramsof microcrystalline cellulose in a V-shaped blender for 15 minutes andthe powder blend was lubricated with magnesium stearate (0.0375kilogram) for additional 5 minutes. Doxycycline monohydrate (0.2kilogram) was granulated with EUDRAGIT® L100 powder (1.280 kilograms)and microcrystalline cellulose powder (0.5 kilograms) using isopropylalcohol as a granulating fluid. The wet granulation was dried in a fluidbed dryer and the dried granulations were blended with magnesiumstearate (0.020 kilogram) in a V-shaped blender for 5 minutes.Doxycycline powder blend and granulation were put on a belayed tabletpress to compress into a belayed tablet with target weights of 200 mgand 100 mg for the powder blend and granulation layers, respectively.

Example 5 Preparation of Immediate-Release Tablet Containing Doxycyclinemonohydrate

Doxycycline monohydrate 1.0 kilogram was blended with 2.225 kilogram ofmicrocrystalline cellulose (AVICEL® PH 102) in a V-shaped blender for 5minutes. The remaining microcrystalline cellulose (1.75 kilogram ofAVICEL® PH 202) is then added to the powder blend in the V-shapedblender and mixed for additional 30 minutes. The powder blend was thenlubricated with magnesium stearate (0.025 kilogram) for 5 minutes. Thelubricated powder blend was compressed into a tablet with the targetweight of 200 mg. The tablets can be further coated with a polymericprotective layer.

Example 6

The simulated blood levels-time profiles at steady state for varioustreatments (e.g., 40 mg once-a-day IR formula, 40 mg once-a-day IR andDR combinations at 70:30 and 80:20 ratios, and twice-a-day 20 mgdoxycycline treatment) were determined by in silico modeling, and areshown in FIG. 4. Using the unique dose (i.e., <50 mg, preferably 40 mg)and composition (IR beads or IR/DR combinations), the steady state bloodlevels of doxycycline of a minimum of about 0.1 ug/ml, preferably about0.3 ug/ml and a maximum of about 1.0 ug/ml, more preferably about 0.8ug/ml, can be achieved to treat such conditions as periodontal and skindiseases.

Example 7

Size 0 capsules containing a ratio of 75:25 of drug-loaded IR pellets toenteric coated DR pellets were prepared as follows. The IR and DRpellets were prepared as set forth in Examples 1 and 2. From the assayvalue of the doxycycline used to make the pellets, it was determinedthat 41.26 mg potency of the capsules would correspond to an actualstrength of 40 mg. doxycycline. The potency of the IR pellets was 194 mgdoxycycline per gram of pellets (mg/g), and for the DR pellets was 133mg/g. Accordingly, it was calculated that for each capsule the fillweight of IR beads would be 159.5 mg, and for DR beads 77.6 mg,corresponding to 75:25 of IR:DR of a 40 mg capsule.

Example 8

A pharmacokinetic (PK) study was conducted in human subjects to comparea first group taking the extended release doxycycline capsule (seeExample 7) (75/25 IR/DR 40 mg) administrated orally once daily versus asecond group taking Periostat® tablets (20 mg) administrated orallytwice daily, twelve hours apart.

Pharmacokinetic blood draws were collected on Nominal Study Day 1 forfirst and second groups, and on Day 7 for the first group as follows: 0(pre dose), 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12 (before the post-morningdose, if applicable), 12.5, 13, 13.5, 14, 14.5, 15, 16, 18, 20, and 24hours after the morning dose.

The data from this study were shown in the following Table 1.

TABLE 1 75/25 IR/DR 75/25 IR/DR Day 7 Periostat ® Day 1 steady state Day1 T_(max) 2.2 2.3  1.9/11.9 C_(max) 562 602 100/333 AUC₀₋₂₄(Hr*ng/ml)5388 7230 4280

Mean C_(max) at Day 1 from the 75/25 IR/DR 40 mg capsules is comparableto that from the Periostat® tablets, and well below the potentialantibiotic effect concentration (1000 ng/ml). The mean C_(min) (177ng/ml at 24-hour time point) is well above the minimum effective plasmaconcentration (100 ng/ml). Individual pharmacokinetic data from both75/25 IR/DR 40 mg capsules and Periostat® 20 mg tablets show that 75/25IR/DR 40 mg capsules provide more consistent in vivo performance interms of less frequency of high peak plasma concentration (>1000 ng/ml)and low plasma concentration (<100 ng/ml) at the end of each dosing.

FIGS. 5 and 6 show two aspects of results obtained from the study. FIG.5 compares the PK profiles of 75:25 IR:DR 40 mg doxycycline formulationsover a 24 hour period on Day 1 and also on Day 7 (steady state). FIG. 6compares the PK profiles of the 75:25 40 mg once daily dosage form andthe Periostat® 20 mg (twice daily) dosage forms.

1-25. (canceled)
 26. A method for treating a collagenase dependentdisease or condition, and/or acute or chronic inflammatory condition ina mammal, comprising administering a daily dose of a tetracyclinecomposition according to claim 1 to the mammal, for at least a timesufficient to ameliorate the disease or condition.
 27. The method ofclaim 26, wherein the mammal is a human.
 28. The method of claim 26,wherein the disease or condition is selected from periodontal disease,rosacea, acne, dry eye, rheumatoid arthritis, hyperparathyroidism, anddiabetes.
 29. The method of claim 28, wherein the disease is periodontaldisease.
 30. The method of claim 29, wherein the tetracycline isdoxycycline.
 31. The method of claim 28, wherein the condition isrosacea.
 32. The method of claim 31, wherein the tetracycline isdoxycycline.
 33. The method of claim 28, wherein the condition is dryeye.
 34. The method of claim 33, wherein the tetracycline isdoxycycline.
 35. The method of claim 30, wherein between 50 mg and 25 mgdoxycycline is present in the composition.
 36. The method of claim 35,wherein about 40 mg doxycycline is present in the composition.
 37. Themethod of claim 30, which is an immediate release composition.
 38. Themethod of claim 30, wherein the composition is in the form of a dosageunit that contains an immediate release portion and a delayed releaseportion.
 39. The method of claim 32, wherein between 50 mg. and 25 mgdoxycycline is present in the composition.
 40. The method of claim 39,wherein about 40 mg doxycycline is present in the composition.
 41. Themethod of claim 32, which is an immediate release composition.
 42. Themethod of claim 32, wherein the composition is in the form of a dosageunit that contains an immediate release portion and a delayed releaseportion.
 43. The method of claim 34, wherein between 50 mg. and 25 mgdoxycycline is present in the composition.
 44. The method of claim 43,wherein about 40 mg doxycycline is present in the composition.
 45. Themethod of claim 34, which is an immediate release composition.
 46. Themethod of claim 34, wherein the composition is in the form of a dosageunit that contains an immediate release portion and a delayed releaseportion
 47. A process for preparing a once-daily oral pharmaceuticalcomposition containing a tetracycline, which will give steady stateblood levels of the tetracycline of a minimum of about 0.1 μg/ml and amaximum of about 1.0 μg/ml, comprising combining between 50 mg and 25 mgdoxycycline with orally pharmaceutically acceptable excipients.
 48. Theprocess of claim 41, wherein the tetracycline is doxycycline.
 49. Anoral pharmaceutical composition for the treatment of a disease or acondition without exerting an antibacterial effect comprising acombination of an immediate release (IR) formulation of doxycycline anda delayed release (DR) formulation of doxycycline, wherein the portionof IR formulation is from about 100 percent to about 70 percent whereinsaid composition at a once-daily dosage will give steady state bloodlevels of doxycycline of a minimum of about 0.1 μg/ml and a maximum ofabout 1.0 μg/ml.
 50. The oral pharmaceutical composition of claim 49 inthe form of pellets, wherein a portion of the pellets is of an IRformulation and the remaining pellets are of a DR formulation coatedwith at least one enteric polymer, and wherein the portion of thepellets of the IR formulation is from about 99 percent to about 70percent of the total pellets.
 51. The oral pharmaceutical composition ofclaim 50, wherein the portion of the pellets of the IR formulation isfrom about 80 percent to about 70 percent of the total pellets.
 52. Theoral pharmaceutical composition of claim 51, wherein the portion of thepellets of the IR formulation is about 75 percent of the total pellets.53. The composition of claim 49, wherein the amount of doxycycline isless than 50 mg.
 54. The composition of claim 52 wherein saidcomposition is contained in a capsule.
 55. An oral pharmaceuticalcomposition of doxycycline, which at once-daily dosage will give steadystate blood levels of the doxycycline of a minimum of about 0.1 μg/mland a maximum of about 1.0 μg/ml, which is a layered pellet, wherein adelayed release (DR) portion having at least one enteric polymercomprises the core of the pellet, and the immediate release portion (IR)surrounds the core.
 56. An oral pharmaceutical composition containingless than about 50 mg of doxycycline, which with once-daily dosingprovides a blood level of the doxycycline between a minimum of about 0.1μg/ml and a maximum of about 1.0 μg/ml wherein the composition does notexert an antibacterial effect and is effective for the treatment of acollagenase-dependent disease or condition.
 57. The composition of claim56, which with once-daily dosing provides the blood level of thedoxycycline between of about 0.3 μg/ml and of about 0.8 μg/ml for theentire course of the treatment.
 58. The composition of claim 56,comprising an immediate release formulation of doxycycline wherein saidimmediate release formulation releases substantially all of thedoxycycline on administration with no enhanced, delayed or extendedrelease effect.
 59. The composition of claim 58, additionally comprisinga delayed release formulation.
 60. The composition of claim 56 in a formof a capsule, a tablet, a pellet, a particle or a gel.
 61. An oralpharmaceutical composition containing a submicrobial amount of atetracycline, wherein the composition does not exert an antibacterialeffect and is effective for the treatment of a collagenase-dependentdisease or condition.
 62. The composition of claim 61, wherein saidcomposition is a combination of an immediate release formulation and adelayed release formulation.
 63. The composition of claim 62 in a formof a layered pellet, wherein a delayed release (DR) formulationcomprising at least one enteric polymer forms the core of the pellet,and the immediate release formulation (IR) surrounds the core.
 64. Thecomposition of claim 62 in the form of pellets, wherein a portion of thepellets is of an IR formulation and the remaining pellets are of a DRformulation coated with at least one enteric polymer, and wherein theportion of the pellets of the IR formulation is from about 99 percent toabout 70 percent of the total pellets.